It is known to blend a polyarylene sulfide and a polyamide as disclosed in JP-B-59-1422 (the term "JP-B" as used herein means an "examined published Japanese patent application"). A mere blend of these two components, though having improved fluidity over the polyarylene sulfide alone, provides molded articles of poor surface properties due to insufficient compatibility between a polyarylene sulfide and a polyamide. In addition, a composition in which a polyamide forms a dispersed phase generally has reduced mechanical strength as compared with a polyamide or a polyarylene sulfide alone. On the other hand, a composition in which a polyamide forms a continuous phase has improved mechanical characteristics, particularly toughness, but has reduced chemical resistance and hot water resistance as compared with a polyarylene sulfide alone.
JP-A-2-169667 (the term "JP-A" as used herein means an "unexamined published Japanese patent application") discloses a composition comprising a modified polyarylene sulfide and a polyamide, the modified polyarylene sulfide being obtained by reacting a polyarylene sulfide prepared from an alkyl substituted dihalo-aromatic compound, a dihalo-aromatic compound, and an alkali metal sulfide with a substituted olefin having at least one functional group selected from a carboxyl group, a carboxylic acid anhydride group, a carboxylic acid ester group, a carboxylic acid metal salt group, an epoxy group, and an imido group in the molecule thereof. According to JP-A-2-169667, the starting polyarylene sulfide to be modified must contain a constituent unit having an alkyl substituent group on the aromatic group because the reaction between the substituted olefin compound as a modifier and the polyarylene sulfide is believed to predominantly take place at this alkyl substituent group moiety. The disclosure is that compatibility with a polyamide is greatly improved by this modification to thereby provide a useful resin composition. In other words, the modifying group should be bonded to the alkyl substituent group moiety of the alkyl substituent group-containing constituent unit but not directly to the aromatic ring.